The present invention relates to an anchoring device. More particularly, the anchoring device of the present invention is intended for use in securing a lifting pin to a concrete member in order to facilitate the lifting and moving thereof.
Anchoring devices for the lifting and moving of concrete members generally comprise an anchoring portion which is embedded within the concrete member and a connecting portion which protrudes from the surface of the concrete. The connecting portion is generally recessed within a void in the concrete surface such that the end of the connecting portion does not protrude beyond the plane of the surface of the concrete member. The connecting portion is constructed so as to releasably attach to a xe2x80x9cpick-up unitxe2x80x9d allowing the concrete member to be moved. Generally more than one anchoring device is used when lifting or moving a concrete member.
A variety of anchors have been used previously in an effort to prevent pull-out during use. These include transverse pins (U.S. Pat. No. 4,580,378), T-(U.S. Pat. No. 4,367,892), V-shaped anchors (U.S. Pat. No. 4,930,269) or additional shear bars (U.S. Pat. No. 4,087,947) and plates (U.S. Pat. No. 5,596,846) to distribute shear stress.
Typical methods involve the use of one of a number of different recess formers that are required to hold the lifting pin in the appropriate recessed position during concrete casting. Recess or void formers of this type need to be removed from the concrete member after the concrete has set.
A further disadvantage with the prior art is the necessity to install the recess former in the concrete whilst such is still wet (U.S. Pat. No. 5,004,208). This process is inconvenient and time consuming. Further, the need to remove the recess former after the concrete has hardened is again time consuming.
The present invention has as one object thereof to overcome substantially, or to at least provide a useful alternative to, the abovementioned problems associated with the prior art.
The preceding discussion of the prior art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia as at the priority date of the application.
Throughout the specification, unless the context requires otherwise, the word xe2x80x9ccomprisexe2x80x9d or variations such as xe2x80x9ccomprisesxe2x80x9d or xe2x80x9ccomprisingxe2x80x9d, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
The present invention provides an anchoring device and a system used to secure an anchoring device embedded within a concrete member. The void former is integrally moulded about the lifting pin. The void former has attachment arms with slots. The slots comprise enlarged terminal portions offset therefrom to suit a range of reinforcement bar/mesh diameters.
Attachment of the anchoring device to the reinforcing bar/mesh distributes shear stress forces into the reinforcing bar/mesh and away from the concrete as well as serving as an anchor member for lifting and thereby preventing the lifting pin from being pulled out of the concrete member.
In accordance with the present invention there is provided an anchoring device adapted to be partially buried in a concrete member during forming thereof for cooperation with a pick-up unit, the anchoring device comprising an integrally formed lifting pin and a void former.
Preferably, the void former is integrally moulded about the lifting pin.
Preferably, the void former is a substantially hemispherical member having a concave inner surface and a convex outer surface. The concave inner surface defines a substantially hollow void.
Preferably, a plurality of attachment arms extend from the convex outer surface of the void former. The attachment arms preferably comprise slots at their terminal ends, the slots comprising enlarged terminal portions offset therefrom.
Preferably, the lifting pin comprises an elongate bar having an enlarged foot, the enlarged foot being adapted to be buried in a concrete member. The lifting pin further comprises an enlarged head, the enlarged head projecting into the void formed in the concrete member by the void former.
The void former is preferably integrally positioned about the elongate bar of the lifting pin at a position such that the enlarged head of the lifting pin is positioned inside the concave portion of the void former such that the head of the lifting pin does not protrude out of the void formed by the void former.
Preferably, the elongate bar between the convex face of the void former and the enlarged foot of the lifting pin is substantially covered by a sleeve. The sleeve is preferably integral to the void former.
The terminal portions of the slots of the attachment arms are preferably adapted to engage reinforcing bar means provided in the concrete member.
Preferably, a plurality of anchoring devices may be provided in the concrete member.